If you increase the frequency of a sound wave four times, what will happen to its speed? A. The speed will increase four times.
B. The speed will decrease four times.
C. The speed will remain the same.
D. The speed will increase twice.
E. The speed will decrease twice.​

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."

snell's law

refractve index = sin incidence / sin refraction

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.